Students create solutions from shrimp shells to keep fresh produce for more than 10 days

When spraying the solution will create a thin film on the surface of agricultural products to avoid insects, microorganisms, mold and reduce oxidation.

At the 2019 post-harvest processing technology competition held in April 2019, the student Bui Thi Khanh Linh , University of Natural Sciences (Ho Chi Minh City National University) left a lot of impression when winning the prize. especially with the study and extraction of denatured chitosan solution from shrimp and crab shells with polyphenols extract in green tea replacing chemicals for long-term preservation of agricultural products.

The study is highly appreciated in the context that Vietnamese agricultural products suffer from high losses after harvest and chemical preservatives are at risk of affecting consumer health.

Bui Thi Khanh Linh - author of biological solution to preserve agricultural products.

The author created the solution by using the hydroxyl, amino and α - methylene reducing agent to create free radicals on the constituent circuit of chitosan , then attaching polyphenols to chitosan circuits. Instead of immersing agricultural products in preservative solutions, the author used the combined pressure spray method to blow wind (mist spray). This way avoids rotting water when excess storage solution clings to agricultural products.

When spraying, the solution creates a thin film on the surface of agricultural products to prevent insects, microorganisms, fungi from developing and reducing the oxidation (aging) due to the possibility of air release to produce agricultural products. Respiratory.

Banana samples preserved with chitosan solution with modified polyphenols ratio of 2: 1 (left), preserved with chitosan (middle) and not preserved (right) after 10 days at room temperature.(Photo: NVCC).

Comparison on banana samples shows that, under normal conditions (room temperature), banana samples do not use preservatives that have matured after 3 days, 5 days start with black spots (oxidized) and on the 7th day rotten.

Banana samples are preserved with polyphenols ripened immediately after 2 days, 4 days appear black spots and 8 days later there are molds on the skin. Samples are sprayed with chitosan solution after 10 days, banana peels only turn yellow and rot in the lower half of the banana.

With chitosan modified mist spray pattern with polyphenols extract with the longest ripening time (about 10 days), the shell remains green, only rots appear at the tip of the stem but no mold on the body, weight decreases little.

According to experts, this research results in a premise to develop a technology chain to preserve and increase the quality of Vietnamese agricultural products for domestic and export markets.

Linh said that in the future, the effect of using chitosan modified with polyphenols extract from green tea and other plants will be compared to find the best source of polyphenols for preserving agricultural products.